US3885382A - Reduced friction watch cannon shafts - Google Patents

Reduced friction watch cannon shafts Download PDF

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Publication number
US3885382A
US3885382A US458813A US45881374A US3885382A US 3885382 A US3885382 A US 3885382A US 458813 A US458813 A US 458813A US 45881374 A US45881374 A US 45881374A US 3885382 A US3885382 A US 3885382A
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United States
Prior art keywords
tube
hour
watch
minute
improvement
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Expired - Lifetime
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US458813A
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English (en)
Inventor
Max Hetzel
Hans Kocher
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SSIH Management Services SA
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SSIH Management Services SA
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Publication date
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B19/00—Indicating the time by visual means
    • G04B19/02—Back-gearing arrangements between gear train and hands
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B31/00—Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor

Definitions

  • FIG. 1 PRIOR ART
  • the present invention relates to watches having at least approximately coaxial minute and hour tubes which rotate with different speeds in the same direction, and from which extend the minute hand and the hour hand, respectively.
  • Almost all known watches employing an analog time display include such an arrangement.
  • In addition to the two coaxial tubes :1 watch is frequently provided with a coaxial axle which carries a second hand and rotates inside the tube to which the minute hand is fixed.
  • watches particularly wrist watches with electrical or electronic driving devices, such as a balance. a tuning fork or a crystal
  • watches of this kind are powered by batteries of 80 to I mA/h which must drive the watch for at least a whole year.
  • a power of about lptW is available at the hour wheel to drive a calendar device or any other mechanism.
  • great effort has been made to reduce the friction and power losses of the gear train so as to have a higher efficiency between the driving device and the display. This would, particularly in electrically or electronically powered watches, make available at the hour wheel the power necessary to drive a calendar device.
  • An object of the present invention is to provide a watch in which the bearings of the minute and the hour tubes respectively permit a higher efficiency and better power transmission than the arrangements now known.
  • a watch having two substantially coaxial tubes carrying the minute and hour hands, respectively is provided with an additional bearing element located between the two coaxial tubes and affixed to the base plate of the watch.
  • the bearing element may be disposed so as to surround the outermost of the two tubes.
  • FIG. I is a top sectional view of a conventional watch
  • FIG. 2 is a top sectional view of a watch according to the invention.
  • FIG. 3 is a top sectional view of a different embodiment of the invention wherein the bearing element surrounds both coaxial tubes;
  • FIG. 4 is a partial front sectional view of a watch ac cording to FIG. 2.
  • FIG. I shows a conventional prior art watch having a second hand in the center, an hour wheel I driven by a pinion 2 and carrying an hour tube 3 onto which an hour hand (not shown) may be affixed.
  • a pinion 4 be longs to a calendar mechanism (not shown).
  • Inside the hour tube 3 rotates a minute tube 5 onto which may be affixed a minute hand (not shown).
  • Located inside the tube 5 is a fixed tube 6, in the center of which can rotate an axle carrying a second hand (both not shown).
  • the hour tube 3 rotates once every l2 hours, the minute tube 5 once every hour and a possible second hand axle (reference number 12 in FIG. 4) once every minute around their respective centers 3a, 5a and 12a.
  • the hour wheel 1 is subjected to two forces K one of which results from the driving pinion 2 and the other of which results from the pinion 4 of the calendar device.
  • a friction and braking effect takes place which results in an important power loss.
  • This power loss is due to the fact that the minute tube 5 is squeezed between the hour tube 3 and the fixed tube 6 by the two forces 2K.
  • Such a conventional bearing of the hour wheel I results in inefficient power transmission. This can easily be proved by means of the following calculation of the power loss and the efficiency of the power transmission arrangement.
  • N power used to drive a calendar device K force transmitted from the pinion 2 to the hour wheel 1 and from the latter to the pinion 4 of the calendar device Nv power loss Da outer diameter of the hour wheel 1 da outer diameter of the minute tube 5 di inner diameter of the minute tube 5 a coefficient of friction "r; efficiency It is known that K1r(Da) [12)(3600) and 1r(da) n-(di) Nv2Ka 3600 +2Ka 3600 Solving both equations for K, setting the solutions equal to each other, and solving for Nv, gives (da +di) Nv 24 0: N,
  • FIG. 2 which differs from FIG. 1 only in that it includes a fixed bearing tube 7 between the hour tube 3 and the minute tube 5, so that both rotating tubes 3 and 5 bear against the immovable bearing tube.
  • the power loss of a watch presenting identical geometrical dimensions as the embodiment described above. but including a fixed tube according to the invention may be calculated as follows. It is known that 2 Ka1r(da) (Ill l3600l N and Solving both equations for K. setting the solutions equal to each other. and solving for N1- gives If da and Du are replaced by their assumed values.
  • FIG. 3 shows an alternate embodiment of the invention which differs slightly from that described above and shown in FIG. 2.
  • the alternative embodiment comprises a fixed bearing tube 7 which is located outside the hour tube 3 and not between the latter and the min ute tube 5 as in the embodiment of FIG. 2. If the bearing tube 7 is precisely formed. the hour tube 3 can never touch the minute tube 5 which rotates around the other fixed tube 6.
  • This embodiment presents the advantage that almost every conventional watch can easily be modified to incorporate the invention. In fact, it is enough to fit a tube 7 into the central opening of the bridge 11 of the calendar device (FIG. 4).
  • FIG. 4 shows in a partial schematic cross-sectional view how the embodiment according to FIG. 2 may be realized.
  • the gear train 8 is of a conventional type.
  • the wheel 9 is. in contrast to conventional watches. located under the plate 10. Only the pinion 2 lies above the plate 10 and under the bridge 11 of the calendar device.
  • the fixed bearing tube 7 which separates the two rotating tubes 3 and 5 respectively, is affixed to the base plate 10. Located inside the minute tube 5 is a second hand axle 12.
  • the bearing tube 7 according to the invention may be made of any conventional bearing material such as. for instance. ruby. beryllium, glucydur. steel. new silver or even brass.
  • the invention is particularly useful in watches driving a calendar device through the hour wheel. but can also serve in all other types of watches and clocks driving any other mechanism by means of the hour wheel.
  • a watch having at least approximately coaxial minute and hour tubes respectively which rotate with different speeds in the same direction and from which one carries the minute hand and the other the hour hand.
  • the improvement comprising a bearing element for preventing friction between said tubes.
  • bearing element is a tube affixed to a bridge of the watch and located outside the hour tube.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromechanical Clocks (AREA)
US458813A 1973-04-18 1974-04-08 Reduced friction watch cannon shafts Expired - Lifetime US3885382A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH583973A CH592910B5 (en]) 1973-04-18 1973-04-18

Publications (1)

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US3885382A true US3885382A (en) 1975-05-27

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ID=4300148

Family Applications (1)

Application Number Title Priority Date Filing Date
US458813A Expired - Lifetime US3885382A (en) 1973-04-18 1974-04-08 Reduced friction watch cannon shafts

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US (1) US3885382A (en])
JP (1) JPS5520198B2 (en])
CH (2) CH592910B5 (en])

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080035453A1 (en) * 2006-08-08 2008-02-14 Mark Haustein Telescoping conveyor with powered and steerable discharge section

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5822154Y2 (ja) * 1977-03-01 1983-05-11 リコ−時計株式会社 時計の表示車支持構造
JPS6021981U (ja) * 1983-07-22 1985-02-15 セイコーインスツルメンツ株式会社 電子時計の輪列構造

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US951139A (en) * 1909-08-06 1910-03-08 Philadelphia Watch Case Company Cannon-pinion shaft.

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS448539Y1 (en]) * 1966-07-01 1969-04-04

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US951139A (en) * 1909-08-06 1910-03-08 Philadelphia Watch Case Company Cannon-pinion shaft.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080035453A1 (en) * 2006-08-08 2008-02-14 Mark Haustein Telescoping conveyor with powered and steerable discharge section

Also Published As

Publication number Publication date
JPS503372A (en]) 1975-01-14
CH583973A4 (en]) 1977-04-15
DE2406785B2 (de) 1977-03-10
JPS5520198B2 (en]) 1980-05-31
CH592910B5 (en]) 1977-11-15
DE2406785A1 (de) 1974-10-31

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